Process for converting light aliphatics to aromatics

ABSTRACT

Aliphatic C 2  to C 12  hydrocarbons are converted in the presence of a particular zeolite catalyst to a mixture of aromatics, optionally containing olefins.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 254,524, filed Oct. 6, 1988, which is a continuation-in-part ofU.S. patent application Ser. No. 98,176, filed Sept. 18, 1987, nowabandoned, which is a continuation-in-part of U.S. patent applicationSer. No. 890,268, filed July 29, 1986, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to a process for converting a paraffinic feedcontaining a major proportion of C₂ to C₁₂ aliphatic hydrocarbons, e.g.,a Udex raffinate, to aromatics, or mixture of aromatics and olefins, inthe presence of a zeolite catalyst.

Zeolitic materials, both natural and synthetic, have been demonstratedin the past to have catalytic properties for various types ofhydrocarbon conversion. Certain zeolitic materials are ordered, porouscrystalline aluminosilicates having a definite crystalline structure asdetermined by X-ray diffraction, within which there are a large numberof smaller cavities which may be interconnected by a number of stillsmaller channels or pores. These cavities and pores are uniform in sizewithin a specific zeolitic material. Since the dimensions of these poresare such as to accept for adsorption molecules of certain dimensionswhile rejecting those of larger dimensions, these materials have come tobe known as "molecular sieves" and are utilized in a variety of ways totake advantage of these properties. Such molecular sieves, both naturaland synthetic, include a wide variety of positive ion-containingcrystalline silicates. These silicates can be described as a rigidthree-dimensional framework of SiO₄ and Periodic Table Group IIIAelement oxide, e.g., AlO₄, in which the tetrahedra are cross-linked bythe sharing of oxygen atoms whereby the ratio of the total Group IIIAelement, e.g., aluminum, and silicon atoms to oxygen atoms is 1:2. Theelectrovalence of the tetrahedra containing the Group IIIA element,e.g., aluminum, is balanced by the inclusion in the crystal of a cation,e.g., an alkali metal or an alkaline earth metal cation. This can beexpressed wherein the ratio of the Group IIA element, e.g., aluminum, tothe number of various cations, such as Ca/2, Sr/2, Na, K or Li, is equalto unity. One type of cation may be exchanged either entirely orpartially with another type of cation utilizing ion exchange techniquesin a conventional manner. By means of such cation exchange, it has beenpossible to vary the properties of a given silicate by suitableselection of the cation. The spaces between the tetrahedra are occupiedby molecules of water prior to dehydration.

Prior art techniques have resulted in the formation of a great varietyof synthetic zeolites. Many of these zeolites have come to be designatedby letter or other convenient symbols, as illustrated by zeolite Z (U.S.Pat. No. 2,882,243); zeolite X (U.S. Pat. No. 2,882,244); zeolite Y(U.S. Pat. No. 3,130,007); zeolite ZK-5 (U.S. Pat. No. 3,247,195);zeolite ZK-4 (U.S. Pat. No. 3,314,752); zeolite ZSM-5 (U.S. Pat. No.3,702,886); zeolite ZSM-11 (U.S. Pat. No. 3,709,979); zeolite ZSM-12(U.S. Pat. No. 3,832,449); zeolite ZSM-20 (U.S. Pat. No. 3,972,983);zeolite ZSM-35 (U.S. Pat. No. 4,016,245); and zeolite ZSM-23 (U.S. Pat.No. 4,076,842), merely to name a few.

The SiO₂ /Al₂ O₃ ratio of a given zeolite is often variable. Forexample, zeolite X can be synthesized with SiO₂ /Al₂ O₃ ratios of from 2to 3; zeolite Y, from 3 to about 6. In some zeolites, the upper limit ofthe SiO₂ /Al₂ O₃ ratio is unbounded. ZSM-5 is one such example whereinthe SiO₂ /Al₂ O₃ ratio is at least 5 and up to the limits of presentanalytical measurement techniques. U.S. Pat. No. 3,941,871 (Reissue U.S.Pat. No. 29,948) discloses a porous crystalline silicate made from areaction mixture containing no deliberately added alumina in the recipeand exhibiting the X-ray diffraction pattern characteristic of ZSM-5.U.S. Pat. Nos. 4,061,724, 4,073,865 and 4,104,294 describe crystallinesilicates of varying alumina and metal content.

Zeolites and alumina have been used in the past in the preparation ofcatalysts for the production of aromatic hydrocarbons from aliphatichydrocarbons. The aliphatic hydrocarbon is passed over the catalyst atan elevated temperature in the liquid or vapor phase. Zeolites ofvarious types have been suggested for the preparation of such catalysts.Examples of such zeolites are mordenite and ZSM-5.

U.S. Pat. No. 3,756,942 discloses a process for converting paraffinicfeedstocks over zeolites such as ZSM-5 to produce a variety ofhydrocarbon products. The underlying chemistry involved in thisconversion is extremely complex. More particularly, a number ofsimultaneous and sometimes competing reactions take place to produce avariety of products which can, in turn, be reacted to form stilldifferent products. These possible reactions include cracking ofparaffins, aromatization of olefins, and alkylation and dealkylation ofaromatics. Products from the conversion of C₅ ⁺ paraffinic feedstocksover ZSM-5 include C₆ -C₈ aromatics, C₂ -C₄ olefins, C₉ ⁺ aromatics andC₁ -C₃ paraffins. Of these products the C₆ -C₈ aromatics and C₂ -C₄olefins are the most desired.

C₆ -C₈ aromatics, e.g., benzene, toluene, xylene and ethyloenzene, alsoreferred to collectively as BTX, are valuable organic chemicals whichcan be used in a variety of ways. Since BTX has a high octane value itcan be used as a blending stock for making high octane gasoline.

C₂ -C₄ olefins, e.g., ethylene, propylene and butene, are also valuableorganic chemicals which can be used to form polymers. By way ofcontrast, C₁ -C₃ paraffins (i.e., methane, ethane and propane),particularly in admixture, are less valuable chemicals which aregenerally used for fuel.

According to U.S. Pat. No. 3,755,486, C₆₋₁₀ hydrocarbons undergodehydrocyclization to benzene and alkylbenzenes in the presence of a Li,Na or K zeolite X or Y or faujasite impregnated with 0.3 to 1.4 percentPt.

U.S. Pat. No. 3,760,024 discloses the aromatization of a feed containingC₂₋₄ paraffins and/or olefins in the absence of added hydrogen employingZSM-5 as catalyst.

According to U.S. Pat. No. 3,855,115, aromatization of hydrocarbons isaccomplished employing rhenium-exchanged ZSM-5.

Aliphatic naphthas are upgraded to products of increased aromaticscontent by the process disclosed in U.S. Pat. No. 3,890,218. The processemploys a zeolite catalyst such as ZSM-5 into which one or more metalswhich increase the aromatization activity of the zeolite, e.g., zinc orcadium, have been incorporated.

In the process disclosed in U.S. Pat. No. 4,347,394 light straight-runnaphthas and similar mixtures are converted to highly aromatic mixtures,principally benzene, employing a Group VIII metal-containingintermediate pore size zeolite, e.g. ZSM-5, which has been renderedsubstantially free of acidity by treatment with an alkali metalcompound, e.g., NaOH.

Gaseous feedstocks containing ethane are converted to a mixture ofbenzene, toluene and xylene ("BTX") in the process of U.S. Pat. No.4,350,835 utilizing a gallium-containing zeolite such as ZSM-5. Asimilar catalyst further containing thorium is disclosed in U.S. Pat.No. 4,629,818.

U.S. Pat. No. 4,435,283 describes a method for dehydrocyclizing alkanesemploying as catalyst a Group VIII metal-containing large pore zeolitewhich further contains an alkaline earth metal, e.g., zeolite X, Y or Lcontaining Pt and barium.

SUMMARY OF THE INVENTION

In accordance with the present invention, a process is provided forproducing one or more aromatic compounds alone or in admixture with oneor more olefins which comprises contacting under suitable conversionconditions a feedstock containing a substantial amount of at least oneC₂ -C₁₂ aliphatic hydrocarbon with a conversion catalyst to provide saidaromatic compound(s) and/or mixture of aromatic compound(s) andolefin(s), said catalyst comprising a synthetic porous crystallinematerial characterized by an X-ray diffraction pattern including valuessubstantially as set forth in Table I, infra.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-3 are graphical representations of process performance datarelating to the aliphatic hydrocarbon conversion process of thisinvention.

DESCRIPTION OF SPECIFIC EMBODIMENTS

The entire contents of applications Ser. Nos. 254,524; 98,176; and890,268 are incorporated herein by reference.

The feed stream to the process of this invention contains at least 20%and more preferably at least 50% by weight of at least one aliphatichydrocarbon containing 2 to 12 carbon atoms. The hydrocarbon may bestraight chain, open chain or cyclic and may be saturated orunsaturated. Some contemplated hydrocarbons are ethane, propane,propylene, n-butane, n-butenes, isobutane, isobutene, straight chain,branched chain and cyclic pentanes, pentenes, hexanes, hexenes,heptanes, heptenes, octanes, octenes, nonanes, nonenes, decanes,undecanes, decenes, undecenes, dodecanes and dodecenes. A particularlyuseful hydrocarbon feedstock herein is a raffinate from a hydrocarbonmixture which has had aromatics removed therefrom by a solventextraction treatment. Examples of such solvent extraction treatments aredescribed on pages 706-709 of the Kirk-Othmer Encyclopedia of ChemicalTechnology, Third Edition, Vol. 9, John Wiley and Sons, 1980. One suchhydrocarbon feedstock is a Udex raffinate, a typical composition ofwhich is as follows:

    ______________________________________                                        Component      Wt. Percent                                                    ______________________________________                                        C.sub.5        6.20                                                           C.sub.5.sup. = 0.19                                                           C.sub.6        45.80                                                          C.sub.6.sup. = 8.49                                                           C.sub.7        27.93                                                          C.sub.7.sup. = 3.56                                                           C.sub.8.sup. 's                                                                              1.87                                                           Benzene        0.39                                                           Toluene        3.85                                                           EB             0.34                                                           Xylene         0.39                                                           C.sub.9.sup. + Aromatics                                                                     1.18                                                           ______________________________________                                    

The synthetic porous crystalline material employed as catalyst in theprocess of this invention is referred to herein as "zeolite MCM-22" orsimply "MCM-22".

Zeolite MCM-b 22 has a composition involving the molar relationship:

    X.sub.2 O.sub.3 :(n)YO.sub.2,

wherein X is a trivalent element, such as aluminum, boron, iron and/orgallium, preferably aluminum, Y is a tetravalent element such as siliconand/or germanium, preferably silicon, and n is at least about 10,usually from about 10 to about 150, more usually from about 10 to about60, and even more usually from about 20 to about 40. In theas-synthesized form, zeolite MCM-b 22 has a formula, on an anhydrousbasis and in terms of xoles of oxides per n moles of YO₂, as follows:

    (0.005-0.1)Na.sub.2 O:(1-4)R:X.sub.2 O.sub.3 :nYO.sub.2

wherein R is an organic. The Na and R components are associated with thezeolite as a result of their presence during crystallization, and areeasily removed by post-crystallization methods hereinafter moreparticularly described.

Zeolite MCM-22 is thermally stable and exhibits high surface area ofgreater than 400 m² /gm as measured by the BET (Bruenauer, Emmet andTeller) test and unusually large sorption capacity when compared topreviously described crystal structures having similar X-ray diffractionpatterns. As is evident from the above formula, MCM-22 is synthesizednearly free of Na cations. It can, therefore, be used as a catalyst withacid activity without an exchange step. To the extent desired, however,the original sodium cations of the as-synthesized material can bereplaced in accordance with techniques well known in the art, at leastin part, by ion exchange with other cations. Preferred replacing cationsinclude metal ions, hydrogen ions, hydrogen precursor, e.g., ammonium,ions and mixtures thereof. Particularly preferred cations are thosewhich tailor the activity of the catalyst for the conversion processherein. These include hydrogen, rare earth metals and metals of GroupsIIA, IIIA, IVA, IB, IIB, IIIB, IVB and VIII of the Periodic Table of theElements.

In its calcined form, zeolite MCM-22 appears to be made up of a singlecrystal phase with little or no detectable impurity crystal phases andhas an X-ray diffraction pattern including the lines listed in Table Ibelow:

                  TABLE I                                                         ______________________________________                                        Interplanar d-Spacing (A)                                                                       Relative Intensity, I/Io × 100                        ______________________________________                                        30.0 ± 2.2     W-M                                                         22.1 ± 1.3     W                                                           12.36 ± 0.2    M-VS                                                        11.03 ± 0.2    M-S                                                         8.83 ± 0.14    M-VS                                                        6.18 ± 0.12    M-VS                                                        6.00 ± 0.10    W-M                                                         4.06 ± 0.07    W-S                                                         3.91 ± 0.07    M-VS                                                        3.42 ± 0.06    VS                                                          ______________________________________                                    

More specifically, the calcined form may be characterized by an X-raydiffraction pattern including the following lines:

                  TABLE II                                                        ______________________________________                                        Interplanar d-Spacing (A)                                                                       Relative Intensity, I/Io × 100                        ______________________________________                                        30.0 ± 2.2     W-M                                                         22.1 ± 1.3     W                                                           12.36 ± 0.2    M-VS                                                        11.03 ± 0.2    M-S                                                         8.83 ± 0.14    M-VS                                                        6.86 ± 0.14    W-M                                                         6.18 ± 0.12    M-VS                                                        6.00 ± 0.10    W-M                                                         5.54 ± 0.10    W-M                                                         4.92 ± 0.09    W                                                           4.64 ± 0.08    W                                                           4.41 ± 0.08    W-M                                                         4.25 ± 0.08    W                                                           4.10 ± 0.07    W-S                                                         4.06 ± 0.07    W-S                                                         3.91 ± 0.07    M-VS                                                        3.75 ± 0.06    W-M                                                         3.56 ± 0.06    W-M                                                         3.42 ± 0.06    VS                                                          3.30 ± 0.05    W-M                                                         3.20 ± 0.05    W-M                                                         3.14 ± 0.05    W-M                                                         3.07 ± 0.05    W                                                           2.99 ± 0.05    W                                                           2.82 ± 0.05    W                                                           2.78 ± 0.05    W                                                           2.68 ± 0.05    W                                                           2.59 ± 0.05    W                                                           ______________________________________                                    

These values were determined by standard techniques. The radiation wasthe K-alpha doublet of copper and a diffractometer equipped with ascintillation counter and an associated computer was used. The peakheights, I, and the positions as a function of 2 theta, where theta isthe Bragg angle, were determined using algorithms on the computerassociated with the diffractometer. From these, the relativeintensities, 100 I/I_(o), where I_(o) is the intensity of the strongestline or peak, and d (obs.) The interplanar spacing in Angstroms Units(A), corresponding to the recorded lines, were determined. In Tables Iand II, the relative intensities are given in terms of the symbolsW=weak, M=medium, S=strong and VS=very strong. In terms of intensities,these may be generally designated as follows:

    W=0-20

    M=20-40

    S=40-60

    VS=60-100

It should be understood that these X-ray diffraction patterns arecharacteristic of all species of zeolite MCM-22. The sodium form as wellas other cationic forms reveal substantially the same pattern with someminor shifts in interplanar spacing and variation in relative intensity.Other minor variations can occur depending on the Y to X, e.g., siliconto aluminum, mole ratio of the particular sample, as well as its degreeof thermal treatment.

Prior to its use as catalyst herein, the MCM-22 crystals should besubjected to thermal treatment to remove part or all of any organicconstituent present therein.

The zeolite MCM-22 catalyst herein can also be used in intimatecombination with a hydrogenating component such as tungsten, vanadium,molybdenum, rhenium, nickel, cobalt, chromium, manganese, or a noblemetal such as platinum or palladium where ahydrogenation-dehydrogenation function is to be performed. Suchcomponent can be introduced in the catalyst composition by way ofcocrystallization, exchanged into the composition to the extent a GroupIIIA element, e.g., aluminum, is in the structure, impregnated thereinor intimately physically admixed therewith. Such component can beimpregnated in, or on, the zeolite such as, for example, by, in the caseof platinum, treating the zeolite with a solution containing a platinummetal-containing ion. Thus, suitable platinum compounds for this purposeinclude chloroplatinic acid, platinous chloride and various compoundscontaining the platinum amine complex.

Zeolite MCM-22, especially in its metal, hydrogen and ammonium forms,can be beneticially converted to another form by thermal treatment. Thisthermal treatment is generally performed by heating one of these formsat a temperature of at least about 370° C. for at least 1 minute andgenerally not longer than 20 hours. While subatmospheric pressure can beemployed for the thermal treatment, atmospheric pressure is preferredsimply for reasons of convenience. The thermal treatment can beperformed at a temperature of up to about 925° C.

Prior to its use in the process of this invention, the zeolite MCM-22crystals should be dehydrated, at least partially. This can be done byheating the crystals to a temperature in the range of from about 200° C.to about 595° C. in an atmosphere such as air, nitrogen, etc. and atatmospheric, subatmospheric or superatmospheric pressures for betweenabout 30 minutes to about 48 hours. Dehydration can also be performed atroom temperature merely by placing the crystalline material in a vacuum,but a longer time is required to obtain a sufficient amount ofdehydration.

Zeolite MCM-22 can be prepared from a reaction mixture containingsources of alkali or alkaline earth metal (M), e.g., sodium orpotassium, cation, an oxide of trivalent element X, e.g, aluminum, anoxide of tetravalent element Y, e.g., silicon, an organic (R) directingagent, hereinafter more particularly described, and water, said reactionmixture having a composition, in terms of xole ratios of oxides, withinthe following ranges:

    ______________________________________                                        Reactants       Useful      Preferred                                         ______________________________________                                        YO.sub.2 /X.sub.2 O.sub.3                                                                     10-60       10-40                                             H.sub.2 O/YO.sub.2                                                                            5-100       10-50                                             OH.sup.- /YO.sub.2                                                                            0.01-1.0    0.1-0.5                                           M/YO.sub.2      0.01-2.0    0.1-1.0                                           R/YO.sub.2      0.05-1.0    0.1-0.5                                           ______________________________________                                    

In a preferred method of synthesizing zeolite MCM-22, the YO₂ reactantcontains a substantial amount of solid YO₂, e.g., at least about 30 wt.%solid YO₂. Where YO₂ is silica, the use of a silica source containing atleast about 30 wt.% solid silica, e.g., Ultrasil (a precipitated, spraydried silica containing about 90 wt.% silica) or HiSil (a precipitatedhydrated SiO₂ containing about 87 wt.% silica, about 6 wt.% free H₂ Oand about 4.5 wt.% bound H₂ O of hydration and having a particle size ofabout 0.02 micron) favors crystal formation from the above mixture andis a distinct improvement over the synthesis method disclosed in U.S.Pat. No. 4,439,409. If another source of oxide of silicon, e.g., Q-Brand(a sodium silicate comprised of about 28.8 wt.% of SiO₂, 8.9 wt.% Na₂ Oand 62.3 wt.% H₂ O) is used, crystallization may yield little if anyMCM-22 crystalline material and impurity phases of other crystalstructures, e.g., ZSM-12, may be produced. Preferably, therefore, theYO₂, e.g., silica, source contains at least about 30 wt.% solid YO₂,e.g., silica, and more preferably at least about 40 wt.% solid YO₂,e.g., silica.

Crystallization of the MCM-22 crystalline material can be carried out ateither static or stirred conditions in a suitable reactor vessel, suchas, e.g., polypropylene jars or teflon lined or stainless steelautoclaves. The total useful range of temperatures for crystallizationis from about 80° C. to about 225° C. for a time sufficient forcrystallization to occur at the temperature used, e.g., from about 25hours to about 60 days. Thereafter, the crystals are separated from theliquid and recovered.

The organic directing agent for use in synthesizing zeolite MCM-22 fromthe above reaction mixture is hexamethyleneimine.

It should be realized that the reaction mixture components can besupplied by more than one source. The reaction mixture can be preparedeither batchwise or continuously. Crystal size and crystallization timeof the MCM-22 crystalline material will vary with the nature of thereaction mixture employed and the crystallization conditions.

In all cases, synthesis of the MCM-22 crystals is facilitated by thepresence of at least about 0.01 percent, preferably about 0.10 percentand still more preferably about 1 percent, seed crystals (based on totalweight of the crystalline product.

The MCM-22 crystals can be shaped into a wide variety of particle sizes.Generally speaking, the particles can be in the form of a powder, agranule, or a molded product such as an extrudate having a particle sizesufficient to pass through a 2 mesh (Tyler) screen and be retained on a400 mesh (Iyler) screen. In cases where the catalyst is molded, such asby extrusion, the crystals can be extruded before drying or partiallydried and then extruded.

It may be desired to incorporate the MCM-22 crystalline material withanother material which is resistant to the temperatures and otherconditions employed in the process of this invention. Such materialsinclude active and inactive materials and synthetic or naturallyoccurring zeolites as well as inorganic materials such as clays, silicaand/or metal oxides such as alumina. The latter my be either naturallyoccurring or in the form of gelatinous precipitates or gels includingmixtures of silica and metal oxides. Use of a material in conjunctionwith zeolite MCM-22, i.e., combined therewith or present during itssynthesis, which itself is catalytically active may change theconversion and/or selectivity of the catalyst. Inactive materialssuitably serve as diluents to control the amount of conversion so thatproducts can be obtained economically and orderly without employingother means for controlling the rate of reaction. These materials may beincorporated into naturally occurring clays, e.g., bentonite and kaolin,to improve the crush strength of the catalyst under commercial operatingconditions. Said materials, i.e., clays, oxides, etc., function asbinders for the catalyst. It is desirable to provide a catalyst havinggood crush strength because in commercial use, it is desirable toprevent the catalyst from breaking down into powder-like materials.These clay binders have been employed normally only for the purpose ofimproving the crush strength of the catalyst.

Naturally occurring clays which can be composited with MCM-22 crystalsinclude the montmorillonite and kaolin family, which families includethe subbentonites, and the kaolins commonly known as Dixie, McNamee,Georgia and Florida clays or others in which the main mineralconstituent is halloysite, kaolinite, dickite, nacrite, or anauxite.Such clays can be used in the raw state as originally mined or initiallysubjected to calcination, acid treatment or chemical modification.Binders useful for compositing with zeolite MCM-22 also includeinorganic oxides, notably alumina.

In addition to the foregoing materials, the MCM-22 crystals can becomposited with a porous matrix material such as silica-alumina,silica-magnesia, silica-zirconia, silica-thoria, silica-beryllia,silica-titania as well asternary compositions such assilica-alumina-thoria, silica-alumina-zirconia, silica-alumina-magnesiaand silica-magnesia-zirconia. It may also be advantageous to provide atleast a part of the foregoing matrix materials in colloidal form so asto facilitate extrusion of the bound catalyst component(s).

The relative proportions of finely divided crystalline material andinorganic oxide matrix vary widely, with the crystal content rangingfrom about 1 to about 90 percent by weight and more usually,particularly when the composite is prepared in the form of beads, in therange of about 2 to about 80 weight percent of the composite.

The stability of the alkylation catalyst of the invention may beincreased by steaming. U.S. Pat. Nos. 4,663,492; 4,594,146; 4,522,929;and 4,429,176, the entire disclosures of which are incorporated hereinby reference, describe conditions for the steam stabilization of zeoIitecatalysts which can be utilized to steam-stabilize the catalyst for useherein. The steam stabilization conditions include contacting thecatalyst with, e.g., 5-100% steam at a temperature of at least about300° C. (e.g., 300°-650° C.) for at least one hour (e.g., 1-200 hours)at a pressure of 101-2,500 kPa. In a more particular embodiment, thecatalyst can be made to undergo steaming with 75-100% steam at 315°-500°C. and atmospheric pressure for 2-25 hours. In accordance with the steamstabilization treatment described in the above-mentioned patents, thesteaming of the catalyst can take place under conditions sufficient toinitially increase the Alpha Value of the catalyst, the significance ofwhich is discussed infra, and produce a steamed catalyst having a peakAlpha Value. If desired, steaming can be continued to subsequentlyreduce the Alpha Value from the peak Alpha Value to an Alpha Value whichis substantially the same as the Alpha Value of the unsteamed catalyst.

The hydrocarbon conversion process of this invention is conducted sothat a feed containing at least 20 wt.% and more preferably at least 50wt.%, of one or more C₂ -C₁₂ aliphatic hydrocarbons is contacted withzeolite MCM-22 in a reaction zone, such as, for example, a fixed orfluid bed of catalyst composition under effective conversion conditions.In a typical embodiment of the process of this invention, the feedstream is introduced into the reaction zone at a temperature within therange of from about 316° C. (600° F.) to about 760° C. (1400° F.), apressure within the range of from about atmospheric to about 400 psigand a liquid hourly space velocity (LHSV) of from about 0.1 hr⁻¹ toabout 5 hr⁻¹.

Preferred temperatures for the process of this invention fall within therange of about 400° C. (752° F.) to about 676.7° C. (1250° F.) andpreferred pressures fall within the range of from about 20 to about 100psig. A preferred LHSV is from about 0.3 to about 3.

In order to more fully illustrate the hydrocarbon conversion process ofthis invention and the manner of practicing same, the following examplesare presented. In examples illustrative of the synthesis of zeoliteMCM-22, whenever sorption data are set forth for comparison of sorptivecapacities for water, cyclohexane and/or n-hexane, they were EquilibriumAdsorption values determined as follows:

A weighed sample of the calcined adsorbent was contacted with thedesired pure adsorbate vapor in an adsorption chamber, evacuated to lessthan 1 mm Hg and contacted with 12 Torr of water vapor or 40 Torr ofn-hexane or 40 torr of cyclohexane vapor, pressures less than thevapor-liquid equilibrium pressure of the respective adsorbate at 90° C.The pressure was kept constant (within about ±0.5 mm Hg) by addition ofadsorbate vapor controlled by a manostat during the adsorption period,which did not exceed about 8 hours. As adsorbate was adsorbed by theMCM-22 crystalline material, the decrease in pressure caused themanostat to open a valve which admitted more adsorbate vapor to thechamber to restore the above control pressures. Sorption was completewhen the pressure change was not sufficient to activate the manostat.The increase in weight was calculated as the adsorption capacity of thesample in g/100 g of calcined adsorbant. Zeolite MCM-22 always exhibitsEquilibrium Adsorption values of greater than about 10 wt.% for watervapor, greater than about 4.5 wt.%, usually greater than about 7 wt.%for cyclohexane vapor and greater than about 10 wt.% for n-hexane vapor.These vapor sorption capacities are a notable distinguishing feature ofzeolite MCM-22.

When Alpha Value is examined, it is noted that the Alpha Value is anapproximate indication of the catalytic cracking activity of thecatalyst compared to a standard catalyst and it gives the relative rateconstant (rate of normal hexane conversion per volume of catalyst perunit time). It is based on the activity of the highly activesilica-alumina cracking catalyst taken as an Alpha of 1 (Rate Constant=0.016 sec⁻¹.). The Alpha Test is described in U.S. Pat. No. 3,354,078,in the Journal of Catalysis, Vol. 4, p. 527 (1965); Vol. 6, p. 278(1966); and Vol. 61, p. 395 (1980), each incorporated herein byreference as to that description. The experimental conditions of thetest used herein include a constant temperature of 538° C. and avariable flow rate as described in detail in the Journal of Catalysis,Vol. 61, p. 395.

EXAMPLE 1

One part of sodium aluminate (43.5% Al₂ O₃,32.2% Na₂ O, 25.6% H₂ O) wasdissolved in a solution containing 1 part of 50% NaOH solution and103.13 parts H₂ O. To this was added 4.50 parts hexamethyleneimine. Theresulting solution was added to 8.55 parts of Ultrasil, a precipitated,spray-dried silica (about 90% SiO₂).

The reaction mixture had the following composition, in mole ratios:

    SiO.sub.2 /Al.sub.2 O.sub.3 =30.0

    OH.sup.- /SiO.sub.2 =0.18

    H.sub.2 O/SiO.sub.2 =44.9

    Na/SiO.sub.2 =0.18

    R/SiO.sub.2 =0.35

where R is hexaxethyleneimine.

The mixture was crystallized in a stainless steel reactor, withstirring, at 150° C. for 7 days. The crystalline product was filtered,washed with water and dried at 120° C. After a 20 hour calcination at538° C., the X-ray diffraction pattern contained the major lines listedin Table III. The sorption capacities of the calcined material weremeasured to be:

    ______________________________________                                        H.sub.2 O            15.2 wt. %                                               Cyclohexane          14.6 wt. %                                               n-Hexane             16.7 wt. %                                               ______________________________________                                    

The surface area of the calcined crystalline material was measured to be494 m² /g.

The chemical composition of the uncalcined material was determined to beas follows:

    ______________________________________                                        Component            wt. %                                                    ______________________________________                                        SiO.sub.2            66.9                                                     Al.sub.2 O.sub.3     5.40                                                     Na                   0.03                                                     N                    2.27                                                     Ash                  76.3                                                     SiO.sub.2 /Al.sub.2 O.sub.3, mole ratio = 21.1                                ______________________________________                                    

                  TABLE III                                                       ______________________________________                                        Degrees        Interplanar                                                    2-Theta        d-Spacing (A)                                                                            I/I.sub.o                                           ______________________________________                                        2.80           31.55      25                                                  4.02           21.98      10                                                  7.10           12.45      96                                                  7.95           11.12      47                                                  10.00          8.85       51                                                  12.90          6.86       11                                                  14.34          6.18       42                                                  14.72          6.02       15                                                  15.90          5.57       20                                                  17.81          4.98        5                                                  20.20          4.40       20                                                  20.91          4.25        5                                                  21.59          4.12       20                                                  21.92          4.06       13                                                  22.67          3.92       30                                                  23.70          3.75       13                                                  24.97          3.57       15                                                  25.01          3.56       20                                                  26.00          3.43       100                                                 26.69          3.31       14                                                  27.75          3.21       15                                                  28.52          3.13       10                                                  29.01          3.08        5                                                  29.71          3.01        5                                                  31.61          2.830       5                                                  32.21          2.779       5                                                  33.35          2.687       5                                                  34.61          2.592       5                                                  ______________________________________                                    

EXAMPLE 2

A portion of the calcined crystalline product of Example 1 was tested inthe Alpha Test and was found to have an Alpha Value of 224.

EXAMPLES 3-5

Three separate synthesis reaction mixtures were prepared withcompositions indicated in Table IV. The mixtures were prepared withsodium aluminate, sodium hydroxide, Ultrasil, hexamethyleneimine (R) andwater. The mixtures were maintained at 150° C., 143° C., and 150° C.,respectively, for 7, 8 and 6 days respectively in stainless steelautoclaves at autogenous pressure. Solids were separated from anyunreacted components by filtration and then water washed, followed bydrying at 120° C. The product crystals were subjected to X-raydiffraction, sorption, surface area and chemical analyses. The resultsof the sorption, surface area and chemical analyses are presented inTable IV. The sorption and surface area measurements were of thecalcined product.

                  TABLE IV                                                        ______________________________________                                        Example           3        4        5                                         ______________________________________                                        Synthesis Mixture, mole ratios                                                SiO.sub.2 /Al.sub.2 O.sub.3                                                                     30.0     30.0     30.0                                      OH.sup.- /SiO.sub.2                                                                             0.18     0.18     0.18                                      H.sub.2 O/SiO.sub.2                                                                             19.4     19.4     44.9                                      Na/SiO.sub.2      0.18     0.18     0.18                                      R/SO.sub.2        0.35     0.35     0.35                                      Product Composition, Wt. %                                                    SiO.sub.2         64.3     68.5     74.5                                      Al.sub.2 O.sub.3  4.85     5.58     4.87                                      Na                0.08     0.05     0.01                                      N                 2.40     2.33     2.12                                      Ash               77.1     77.3     78.2                                      SiO.sub.2 /Al.sub.2 O.sub.3, mole ratio                                                         22.5     20.9     26.0                                      Adsorption, Wt. %                                                             H.sub.2 O         14.9     13.6     14.6                                      Cyclohexane       12.5     12.2     13.6                                      n-Hexane          14.6     16.2     19.0                                      Surface Area, m.sup.2 /g                                                                        481      492      487                                       ______________________________________                                    

EXAMPLE 6

Quantities of the calcined (538° C. for 3 hours) crystalline silicateproducts of Examples 3, 4 and 5 were tested in the Alpha Test and foundto have Alpha Values of 227, 180 and 187, respectively.

EXAMPLE 7

To demonstrate a further preparation of the present zeolite, 4.49 partsof hexamethyleneimine was added to a solution containing 1 part ofsodium aluminate, 1 part of 50% NaOH solution and 44.19 parts of H₂ O.To the combined solution were added 8.54 parts of Ultrasil silica. Themixture was crystallized with agitation at 145° C. for 59 hours and theresultant product was water washed and dried at 120° C.

Product chemical composition, surface area and adsorption analysesresults were as set forth in Table V:

                  TABLE V                                                         ______________________________________                                        Product Composition uncalcined                                                C                       12.1   wt. %                                          N                       1.98   wt. %                                          Na                      640    ppm                                            Al.sub.2 O.sub.3        5.0    wt. %                                          SiO.sub.2               74.9   wt. %                                          SiO.sub.2 /Al.sub.2 O.sub.3, mole ratio                                                               25.4                                                  Adsorption, wt. %                                                             Cyclohexane             9.1                                                   N-Hexane                14.9                                                  H.sub.2 O               16.8                                                  Surface Area, m.sup.2 /g                                                                              479                                                   ______________________________________                                    

EXAMPLE 8

Twenty-five grams of solid crystal product from Example 7 were calcinedin a flowing nitrogen atmospheres at 538° C. for 5 hours, followed bypurging with 5% oxygen gas (balance N₂) for another 16 hours at 538° C.

Individual 3 g samples of the calcined material were ion-exchanged with100 ml of 0.1N TEABr, TPABr and LaCl₃ solution separately. Each exchangewas carried out at ambient temperature for 24 hours and repeated threetimes. The exchanged samples were collected by filtration, water-washedto be halide-free and dried. The compositions of the exchanged samplesare tabulated below demonstrating the exchange capacity of the presentcrystalline silicate for different ions.

    ______________________________________                                                       Exchange Ions                                                  Ionic Composition, wt. %                                                                       TEA        TPA    La                                         ______________________________________                                        Na                0.095      0.089  0.063                                     N                0.30       0.38   0.03                                       C                2.89       3.63   --                                         La               --         --     1.04                                       ______________________________________                                    

EXAMPLE 9

The La-exchanged sample from Example 8 was sized to 14 to 25 mesh andthen calcined in air at 538° C. for 3 hours. The calcined material hadan Alpha Value of 173.

EXAMPLE 10

The calcined sample La-exchanged material from Example 9 was severelysteamed at 649° C. in 100% steam for 2 hours. The steamed sample had anAlpha Value of 22, demonstrating that the zeolite has very goodstability under severe hydrothermal treatment.

EXAMPLE 11

This example illustrates the preparation of the present zeolite where Xin the general formula, supra, is boron. Boric acid, 2.59 parts, wasadded to a solution containing 1 part of 45% KOH solution and 42.96parts H₂ O. To this was added 8.56 parts of Ultrasil silica, and themixture was thoroughly homogenized. A 3.88 parts quantity ofhexamethyleneimine was added to the mixture.

The reaction mixture had the following composition in mole ratios:

    SiO.sub.2 /B.sub.2 O.sub.3 =6.1

    OH.sup.- /SiO.sub.2 =0.06

    H.sub.2 O/SiO.sub.2 =19.0

    K/SiO.sub.2 =0.06

    R/SiO.sub.2 =0.30

where R is hexamethyleneimine.

The mixture was crystallized in a stainless steel reactor, withagitation, at 150° C. for 8 days. The crystalline product was filtered,washed with water and dried at 120° C. A portion of the product wascalcined for 6 hours at 540° C. and found to have the following sorptioncapacities:

    ______________________________________                                        H.sub.2 O (12 Torr)   11.7   wt. %                                            Cyclohexane (40 Torr) 7.5    wt. %                                            n-Hexane (40 Torr)    11.4   wt. %                                            ______________________________________                                    

The surface area of the calcined crystalline material was measured (BET)to be 405m² /g.

The chemical composition of the uncalcined material was determined to beas follows:

    ______________________________________                                        N                       1.94   wt. %                                          Na                      175    ppm                                            K                       0.60   wt. %                                          Boron                   1.04   wt. %                                          Al.sub.2 O.sub.3        920    ppm                                            SiO.sub.2               75.9   wt. %                                          Ash                     74.11  wt. %                                          SiO.sub.2 /Al.sub.2 O.sub.3, molar ratio = 1406                               SiO.sub.2 /(Al+B).sub.2 O.sub.3, molar ratio = 25.8                           ______________________________________                                    

EXAMPLE 12

A portion of the calcined crystalline product of Example 11 was treatedwith NH₄ Cl and again calcined. The final crystalline product was testedin the Alpha Test and found to have an Alpha Value of 1.

EXAMPLE 13

This example illustrates another preparation of the zeolite in which Xof the general formula, supra, is boron. Boric acid, 2.23 parts, wasadded to a solution of 1 part of 50% NaOH solution and 73.89 parts H₂ O.To this solution was added 15.29 parts of HiSil silica followed by 6.69parts of hexamethyleneimine. The reaction mixture had the followingcomposition in mole ratios:

    SiO.sub.2 /B.sub.2 O.sub.3 =12.3

    OH.sup.- /SiO.sub.2 =0.056

    H.sub.2 O/SiO.sub.2 =18.6

    K/SiO.sub.2 =0.056

    R/SiO.sub.2 =0.30

where R is hexamethyleneimine.

The mixture was crystallized in a stainless steel reactor, withagitation, at 300° C. for 9 days. The crystalline product was filtered,washed with water and dried at 120° C. The sorption capacities of thecalcined material (6 hours at 540° C.) were measured:

    ______________________________________                                        H.sub.2 O (12 Torr)   14.4   wt. %                                            Cyclohexane (40 Torr) 4.6    wt. %                                            n-Hexane (40 Torr)    14.0   wt. %                                            ______________________________________                                    

The surface area of the calcined crystalline material was measured to be438m² /g.

The chemical composition of the uncalcined material was determined to beas follows:

    ______________________________________                                        Component              Wt. %                                                  ______________________________________                                        N                      2.48                                                   Na                     0.06                                                   Boron                  0.83                                                   Al.sub.2 O.sub.3       0.50                                                   SiO.sub.2              73.4                                                   SiO.sub.2 /Al.sub.2 O.sub.3,molar ratio = 249                                 SiO.sub.2 /(Al+B).sub.2 O.sub.3,molar ratio = 28.2                            ______________________________________                                    

EXAMPLE 14

A portion of the calcined crystalline product of Example 13 was testedin the Alpha Test and found to have an Alpha Value of 5.

EXAMPLES 15-19 AND COMPARISON EXAMPLES 20-26

Examples 15 to 19 illustrate the conversion of the Udex raffinate whosecomposition is set forth above over zeolite MCM-22 to provide a productmixture containing substantial amounts of BTX aromatics together withother aromatic and aliphatic hydrocarbons. Examples 20 to 26 illustratethe use of unbound ZSM-5 for conversion of the same feedstock under thesame conditions.

The zeolite MCM-22 used in Examples 15-19 was prepared by adding 4.49parts quantity of hexamethyleneimine to a mixture containing 1.00 partsodium aluminate, 1.00 part 50% NaOH, 8.54 parts Ultrasil VN3 and 44.19parts deionized H₂ O. The reaction mixture was heated to 143° C. (290°F.) and stirred in an autoclave at that temperature for crystallization.After full crystallinity was achieved, the majority of thehexaxethyleneimine was removed from the autoclave by controlleddistillation and the zeolite crystals separated from the remainingliquid by filtration, washed with deionized H₂ O and dried. The zeolitewas then calcined in nitrogen at 540° C., exchanged with an aqueoussolution of ammonium nitrate and calcined in air at 540° C. The zeolitewas tabletted, crushed and sized to 30/40 mesh and loaded into thefixed-bed downflow reactor at a constant MCM-22 loading of 0.5 gm.

The MCM-22 catalyst had the following properties (Table VI):

                  TABLE VI                                                        ______________________________________                                        Properties of the MCM-22 Conversion Catalyst                                  ______________________________________                                        Surface Area (BET), m.sup.2 /g                                                                    503                                                       SiO.sub.2 /Al.sub.2 O.sub.3 (molar)                                                               27                                                        Na, ppm             495                                                       Alpha               693                                                       Sorption Properties, wt. %                                                    H.sub.2 O           15.0                                                      CyC.sub.6           12.5                                                      n-C.sub.6           16.0                                                      Ash at 1000° C., wt. %                                                                     99.05                                                     ______________________________________                                    

Zeolite ZSM-5 which was used in Examples 20 to 26 (SiO₂ Al₂ O₃ =55 wasprepared in a conventional manner.

Reaction conditions for Examples 15 to 26 were 538° C., 1 atm and 2-30WHSV.

The analyses of the conversion products of Examples 15-26 is set forthin Table VII as follows:

                                      TABLE VII                                   __________________________________________________________________________    Conversion of Udex Raffinate Over Zeolite Catalysts                           Example   15   16   17   18   19   20  21  22  23  24  25  26                 __________________________________________________________________________    Zeolite   MCM-22                                                                             MCM-22                                                                             MCM-22                                                                             MCM-22                                                                             MCM-22                                                                             ZSM-5                                                                             ZSM-5                                                                             ZSM-5                                                                             ZSM-5                                                                             ZSM-5                                                                             ZSM-5                                                                             ZSM-5              WHSV      26   13   6.6  2.6  1.3  26  26  13  13  6.6 6.6 2.6                Pressure  atm  atm  atm  atm  atm  atm atm atm atm atm atm atm                Temperature, °C.                                                                 538  538  538  538  538  538 538 538 538 538 538 538                TOS, hr   1    3    4    7    9    1   2   4   5   6   8   10                 Product Analysis,                                                             wt. %                                                                         Hydrogen  0.49 0.62 0.87 1.33 1.58 0.55                                                                              0.59                                                                              0.38                                                                              0.83                                                                              0.11                                                                              0.52                                                                              0.11               Methane   1.40 2.18 2.27 2.82 3.48 1.03                                                                              0.95                                                                              1.80                                                                              1.45                                                                              3.07                                                                              2.76                                                                              5.09               Ethane    2.58 3.82 4.00 4.59 5.60 2.20                                                                              2.17                                                                              3.58                                                                              3.06                                                                              5.87                                                                              5.22                                                                              8.41               Ethylene  3.11 3.59 3.36 2.71 2.28 3.23                                                                              3.21                                                                              4.26                                                                              3.57                                                                              4.93                                                                              4.56                                                                              4.77               Propane   9.97 14.24                                                                              15.05                                                                              15.60                                                                              16.36                                                                              7.51                                                                              7.19                                                                              12.02                                                                             10.22                                                                             18.34                                                                             16.96                                                                             25.10              Propylene 7.95 7.54 6.43 4.48 3.39 7.76                                                                              7.77                                                                              9.33                                                                              7.77                                                                              9.59                                                                              8.92                                                                              7.55               Butanes   8.72 9.57 7.75 6.60 5.99 6.27                                                                              6.17                                                                              9.44                                                                              7.94                                                                              12.42                                                                             11.63                                                                             13.17              Butenes   4.60 4.53 3.80 2.44 2.09 4.90                                                                              4.92                                                                              5.50                                                                              4.89                                                                              4.99                                                                              5.24                                                                              4.15               Pentanes  4.97 4.15 3.46 2.40 2.01 4.92                                                                              4.87                                                                              4.98                                                                              4.60                                                                              4.37                                                                              4.49                                                                              3.30               Pentenes  1.48 1.42 1.15 0.80 0.61 1.81                                                                              1.84                                                                              1.79                                                                              1.73                                                                              1.54                                                                              1.60                                                                              1.12               Hexanes   27.43                                                                              20.30                                                                              20.44                                                                              16.16                                                                              14.37                                                                              33.74                                                                             33.63                                                                             25.27                                                                             26.17                                                                             16.08                                                                             16.12                                                                             7.95               Hexenes   2.85 2.24 1.98 2.20 1.67 0.60                                                                              0.76                                                                              0.40                                                                              0.52                                                                              0   0   0.18               Heptanes  13.27                                                                              10.22                                                                              10.05                                                                              10.79                                                                              9.02 14.72                                                                             14.90                                                                             10.32                                                                             11.26                                                                             6.57                                                                              5.73                                                                              3.20               Heptenes  0.73 0.67 0.69 1.35 1.01 0.89                                                                              0.92                                                                              0.76                                                                              0.81                                                                              0   0   0.37               Benzene   1.26 2.08 2.60 4.42 5.88 1.01                                                                              1.01                                                                              1.56                                                                              1.56                                                                              2.16                                                                              2.05                                                                              3.44               Toluene   4.43 5.90 7.07 10.28                                                                              13.28                                                                              4.61                                                                              4.61                                                                              6.25                                                                              6.46                                                                              6.13                                                                              6.95                                                                              7.78               Ethylbenzene                                                                            0.39 0.63 0.91 1.10 1.18 0.32                                                                              0.32                                                                              0.49                                                                              0.52                                                                              0.30                                                                              0.49                                                                              0.39               Xylenes   2.18 3.44 4.33 4.97 5.89 1.78                                                                              1.85                                                                              0.32                                                                              3.59                                                                              2.02                                                                              3.75                                                                              3.08               Trimethylbenzenes                                                                       1.16 1.63 3.79 2.47 2.08 1.12                                                                              1.11                                                                              1.16                                                                              2.00                                                                              0.90                                                                              1.84                                                                              0.74               C.sub.10 .sup.+  Aromatics                                                              1.03 1.24 0    2.66 2.22 1.03                                                                              1.20                                                                              0.39                                                                              1.05                                                                              0.62                                                                              1.18                                                                              0.34               __________________________________________________________________________

FIG. 1 compares aromatics selectivity for both ZSM-5 and MCM-22. At 25to 40% aromatizable conversion, MCM-22 shows significantly higheraromatics selectivity than the ZSM-5. Similarly, FIG. 2 shows thataromatics yield is also enhanced substantially employing MCM-22.

In the Figures, Aromatic Selectivity and Aromatizables are defined asfollows: ##EQU1## all terms in weight percent of product, andAromatizables=ethylene+higher molecular weight non-aromatic compounds(e.g. C₃ ⁺ non-aromatics).

EXAMPLES 27-29

These examples illustrate the conversion of n-hexane over a catalystcontaining the zeolite of the invention. The zeolite was produced byadding 4.49 parts, by weight, of hexamethyleneimine to a mixturecontaining 1.00 part sodium aluminate, 1.00 part 50% NaOH, 8.54 partsUltrasil VN3 silica and 44.19 parts deionized H₂ O. The reaction mixturewas heat to 143° C. (290° F.) and stirred in an autoclave at thattemperature for crystallization. After full crystallinity was achieved,the majority of the hexamethyleneimine was removed from the autoclave bycontrolled distillation and the zeolite crystals separated from theremaining liquid by filtration, washed with deionized H₂ O and dried.

A portion of the zeolite crystals was combined with Al₂ O₃ to form amixture of 65 parts, by weight, zeolite and 35 parts Al₂ O₃. Water wasadded to this mixture to allow the resulting catalyst to be formed intoextrudates. The catalyst was activated by calcining at 482° C. (900° F.)in 3 v/v/min nitrogen for three hours, then treated with 50% vol.%air/50 vol.% N₂ at 3 v/v/min, also at 482° C. (900° F.). The calcinationwas completed by raising the temperature to 540° C. (1000° F.) at5°F./min and finally switching to 100% air (3 v/v/min) and holding at540° C. (1000° F.) for three hours.

In each of the examples, the n-hexane conversion was effected at 540°C., 100 kPa (atmospheric) pressure and an LHSV of 0.6. Table VIII setsforth the results of the conversions and FIG. 3 shows the yield ofaromatics against the percentage of conversion for the combined results.

                  TABLE VIII                                                      ______________________________________                                                      Example                                                                        27       28     29                                                           Time on Stream (hrs)                                            Products:       6          30     54                                          ______________________________________                                        H.sub.2         0.67       0.58   0.55                                        Methane         3.97       3.24   3.71                                        Ethane          12.34      11.38  12.68                                       Propane         24.84      23.97  27.08                                       Butanes         11.05      9.27   8.90                                        Pentanes        1.52       1.04   0.93                                        n-Hexane        7.24       5.44   6.81                                        C.sub.6 + P+O   1.29       2.51   2.75                                        Ethylene        4.42       4.63   4.72                                        Propylene       7.48       8.90   7.16                                        C.sub.4 Olefins 4.51       7.07   5.61                                        C.sub.5 Olefins 1.32       2.44   2.35                                        Benzene         2.30       2.55   2.52                                        Toluene         5.31       4.88   4.25                                        A.sub.8         4.65       5.15   4.86                                        A.sub.9 +       7.09       6.95   5.12                                        Aromatics selectivity                                                                         54.25      57.19  50.54                                       ______________________________________                                    

EXAMPLE 30

This example illustrates the use of the present zeolite for n-hexaneconversion after the zeolite has been steamed (100% steam) at 540° C.(1000° F.) for 48 hours. The reaction conditions were essentially thesame as those employed in Examples 27-29.

The results of the conversion herein are set forth in Table IX asfollows:

                  TABLE IX                                                        ______________________________________                                                        Time On Stream (hrs.)                                         Products:       6                                                             ______________________________________                                        H.sub.2         0.11                                                          Methane         2.02                                                          Ethane          4.96                                                          Propane         8.13                                                          Butanes         2.33                                                          Pentanes        0.16                                                          n-Hexane        52.30                                                         C.sub.6 + P+O   2.36                                                          Ethylene        4.02                                                          Propylene       11.18                                                         C.sub.4 Olefins 1.96                                                          C.sub.5 Olefins 0.22                                                          Benzene         2.44                                                          Toluene         5.09                                                          A.sub.8         1.94                                                          A.sub.9 +       0.78                                                          Aromatics selectivity                                                                         59.49                                                         ______________________________________                                    

WHAT IS CLAIMED IS:
 1. A process for producing one or more aromaticcompounds alone or in admixture with one or more olefins which comprisescontacting under suitable conversion conditions a feedstock containing asubstantial amount of at least one C₂ -C₁₂ aliphatic hydrocarbon with aconversion catalyst to provide said aromatic compound(s) and/or mixtureof aromatic compound(s) and olefin(s), said catalyst comprising asynthetic porous crystalline material characterized by an X-raydiffraction pattern including values substantially as set forth in TableI of the specification.
 2. The process of claim 1 wherein the syntheticporous crystalline material is characterized by an X-ray diffractionpattern including values substantially as set forth in Table II of thespecification.
 3. The process of claim 1 wherein the synthetic porouscrystalline material has a composition comprising the molar relationship

    X.sub.2 O.sub.3 :(n)YO.sub.2,

wherein n is at least about 10, X is a trivalent element and Y is atetravalent element.
 4. The process of claim 2 wherein the syntheticporous crystalline material has a composition comprising the molarrelationship:

    X.sub.2 O.sub.3 :(n)YO.sub.2,

wherein n is at least about 10, X is a trivalent element and Y is atetravalent element.
 5. The process of claim 1 wherein the syntheticporous crystalline material possesses equilibrium adsorption capacitiesof greater than about 4.5 wt.% for cyclohexane vapor and greater thanabout 10 wt.% for n-hexane vapor.
 6. The process of claim 3 wherein X isselected from the group consisting of aluminum, boron, gallium andcombinations thereof and Y is selected from the group consisting ofsilicon, germanium and combinations thereof.
 7. The process of claim 3wherein X comprises aluminum and Y comprises silicon.
 8. The process ofclaim 1 wherein said synthetic porous crystalline material has beentreated to replace original cations, at least in part, with a cation ormixture of cations selected from the group consisting of hydrogen,hydrogen precursors, rare earth metals, and metals of Groups IIA, IIIA,IVA, IB, IIB, IIIB, IVB, VIB and VIII of the Periodic Table.
 9. Theprocess of claim 1 wherein said synthetic porous crystalline materialhas been thermally treated at a temperature up to about 925° C. in thepresence or absence of steam.
 10. The process of claim 8 wherein saidsynthetic porous crystalline material has been-thermally treated at atemperature up to about 925° C. in the presence or absence of steam. 11.The process of claim 1 wherein said synthetic porous crystallinematerial is combined with a matrix material.
 12. The process of claim 11wherein said matrix material is a silica or alumina-containing material.13. The process of claim 12 wherein the catalyst is provided in the formof extrudate, beads or fluidizable microspheres.
 14. The process ofclaim 1 wherein the feedstock contains at least about 50% by weight ofat least one C₂ -C₁₂ aliphatic hydrocarbon.
 15. The process of claim 1wherein the feedstock is a raffinate from a hydrocarbon mixture fromwhich one or more aromatics have been removed by solvent extraction. 16.The process of claim 1 wherein the feedstock is a Udex raffinate. 17.The process of claim 1 carried out at a temperature of from about 600°F. to about 1400° F., a pressure of from atmospheric to about 400 psigand an LHSV of from about 0.1 hr⁻ to about 5 hr⁻¹.
 18. The process ofclaim 11 wherein said matrix material comprises zirconia, titania ormixtures thereof.